Application of a remote-sensing three-source energy balance model to improve evapotranspiration partitioning in vineyards

Authors: BURCHARD-LEVINE, V. - Us Geological Survey (USGS); NIETO, H. - University Of Alcala; Kustas, William - Bill; Gao, Feng; Alfieri, Joseph; Prueger, John; HIPPS, L. - Utah State University; BAMBACH, N. - University Of California, Davis; McElrone, Andrew; CASTRO, S. - University Of California, Davis; ALSINAM. - E & J Gallo Winery; McKee, Lynn; ZHAN, E. - Princeton University; BOU-ZEID, E - Collaborator; DOKOOZLIAN, N - E & J Gallo Winery

Submitted to: Irrigation Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/15/2022
Publication Date: 4/5/2022
Citation: Burchard-Levine, V., Nieto, H., Kustas, W.P., Gao, F.N., Alfieri, J.G., Prueger, J.H., Hipps, L.E., Bambach, N., McElrone, A.J., Castro, S., Alsina., McKee, L.G., Zhan, E., Bou-Zeid, E., Dokoozlian, N. 2022. Application of a remote-sensing three-source energy balance model to improve evapotranspiration partitioning in vineyards. Irrigation Science. 40:593-608. https://doi.org/10.1007/s00271-022-00787-x.
DOI: https://doi.org/10.1007/s00271-022-00787-x

Interpretive Summary: Improved accuracy of evapotranspiration (ET) estimation, including its partitioning between transpiration (T) and surface evaporation (E), is key to monitor agricultural water use in vineyards, especially to enhance water use efficiency in water limited regions such as California. Remote sensing methods have shown great utility in retrieving ET from surface energy balance models based on thermal infrared data. Notably, the two-source energy balance (TSEB) has been widely and robustly applied in numerous landscapes, including vineyards. However, vineyards add an additional complexity where the landscape is essentially made up of two distinct zones: the grapevine and the interrow, which is often seasonally covered by an herbaceous cover crop. A remote sensing based three-source energy balance (3SEB) model, which employs an additional vegetation source to TSEB, was applied in an experimental vineyard located in California´s Central Valley to investigate whether it improves the depiction of the ET sources from the grapevine-interrow system. 3SEB improved upon TSEB simulations, with the largest differences being concentrated in the spring and early summer seasons, when there are ET sources from both grapevine foliage and the cover crop. Additionally, the 3SEB’s modelled ET partitioning between T and E compared well against an independent estimate. Improved knowledge of T and E has the potential to enhance grapevine water stress detection to support irrigation management decisions in conserving water resources.

Technical Abstract: Improved accuracy of evapotranspiration (ET) estimation, including its partitioning between transpiration (T) and surface evaporation (E), is key to monitor agricultural water use in vineyards, especially to enhance water use efficiency in semi-arid regions such as California, USA. Remote sensing methods have shown great utility in retrieving ET from surface energy balance models based on thermal infrared data. Notably, the two-source energy balance (TSEB) has been widely and robustly applied in numerous landscapes, including vineyards. However, vineyards add an additional complexity where the landscape is essentially made up of two distinct zones: the grapevine and the interrow, which is often seasonally covered by an herbaceous cover crop. Therefore, it becomes more complex to disentangle the different contributions of the different vegetation elements to total ET, especially through TSEB, which assumes a single vegetation source over a soil layer. As such, a remote sensing based three-source energy balance (3SEB) model, which essentially adds a vegetation source to TSEB, was applied in an experimental vineyard located in California´s Central Valley to investigate whether it improves the depiction of the grapevine-interrow system. The model was applied in four different blocks in 2019 and 2020, where each block had an eddy-covariance (EC) tower collecting continuous flux, radiometric and meteorological measurements. 3SEB’s latent and sensible heat flux retrievals were highly accurate with an overall RMSD < 50 W/m^2 compared to EC measurements. 3SEB improved upon TSEB simulations, with the largest differences being concentrated in the spring and summer seasons, when there is greater mixing between grapevine foliage and the cover crop. Additionally, the 3SEB’s modelled ET partitioning (T/ET) compared well against an EC T/ET retrieval method, being only slightly underestimated while also observing certain seasonal differences. Overall, these promising results indicate 3SEB can be of great utility of vineyard irrigation management, especially to improve T/ET estimations and to quantify the contribution of the cover crop to ET. Improved knowledge of T/ET can enhance grapevine water stress detection to support irrigation and water resource management